Testing system and testing method for structure

ABSTRACT

The present invention discloses a testing system and a testing method for a structure which tests a structure made of a test piece structure and a numerical model virtually connected to the structure. A simulated structure including a frame, an actuator and a reaction force measuring device is mounted on a foundation on which a shaking table is also mounted. Only the test piece structure is mounted on the shaking table. The motion of the shaking table  5  which is generated at the time of shaking the test piece structure using the shaking table and the actuator is measured by a shaking table motion measuring device, while the reaction force generated by the test piece structure is measured by a reaction force measuring device. Using these measured values and the numerical model stored in a digital computer, the motion of the test piece structure after a predetermined period for the motion of the simulated structure is calculated. The actuator and the shaking table are driven so as to make this calculated motion.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a testing system and a testingmethod for a structure, and more particularly to a testing system and atesting method for a structure which can be preferably used for anearthquake resistance test.

[0002] To evaluate the earthquake resistance of a structure, it becomesnecessary to evaluate not only the linear deformation of the structurebut also the non-linear deformation and the rupture phenomenon of thestructure. For this purpose, a testing method where a test is carriedout by combining the simulation of the behavior of the structure using acomputer and a shaking test which actually shakes a test piece using ashaking table and an actuator has been put into practice. This testingmethod has an advantage that it can carry out the test using the testpiece which has a size close to a size of an actual structure. However,since both the actuator and the test piece are mounted on the shakingtable, the actual situation is that the test piece which is mounted onthe shaking table must be small-sized compared to the size of theshaking table. Conventionally, at the time of testing a structure, thetest piece, the actuator for shaking the test piece and a reaction wallfor the actuator are all mounted on the shaking table. Such an exampleis described in JP-A-7-55630.

[0003] As described above, in the test which combines the simulationusing the computer and the shaking test which tests the actual testpiece using the shaking table and the actuator, the test can be carriedout using the test piece having the size similar to that of the actualstructure. However, in the testing method described in the known examplewhich mounts the reaction wall for the actuator on the shaking table thepart of the shaking table is occupied by this reaction wall.Accordingly, only the remaining part of the shaking table can be usedfor the test piece so that such a method is less optimal in view of theeffective use of the shaking table. Therefore, the advantage that thelarge structure can be tested is hampered and thus reducing the spacefor the reaction wall is required in terms of the preparation of theexpensive shaking table facilities.

SUMMARY OF THE INVENTION

[0004] The present invention has been made to solve the above mentionedinconveniences and it is an object of the present invention to provide atesting system and a testing method which can sufficiently make use ofthe size of the shaking table and can carry out a test on a test piecehaving a size close to a size of an actual structure.

[0005] It is another object of the present invention to provide atesting system and a testing method for a structure which can make useof an entire space of the shaking table. Furthermore, the presentinvention can achieve the above objects with a simple constitutionwithout adding any comprehensive modifications to a shaking tabledevice.

[0006] The first aspect of the present invention to achieve the aboveobjects is that a testing system for a structure which tests a structuremade of a partial structure and a numerical model virtually connected tothis partial structure comprises a shaking table on which the partialstructure is mounted, a simulated structure which includes an actuatorfor shaking the partial structure and reaction force measuring means formeasuring a reaction force which it receives from the partial structurewhen the partial structure is shaken, and a digital computer whichcalculates the motion of the numerical model based on the measuredvalues of the reaction force measuring means and generates a shakingsignal for the actuator based on the calculated result, and the shakingtable and the simulated structure are mounted on a same foundation.

[0007] The second aspect of the present invention to achieve the aboveobjects is that the testing system comprises a shaking table which ismounted on a foundation by way of a first actuator, a simulatedstructure having at least one second actuator which is fixedly mountedon a foundation which is common to the foundation on which the shakingtable is mounted, a reaction force measuring device which measures areaction force generated by a test piece structure connected to thesimulated structure, a digital computer which stores a numerical modelvirtually connected to the test piece structure, a controller whichcontrols the simulated structure, and a shaking table motion measuringdevice which measures the motion of the shaking table.

[0008] It is preferable that the digital computer outputs a controlsignal to the controller based on outputs of the shaking table motionmeasuring device and the reaction force measuring device. It is alsopreferable that the digital computer calculates the motion of the testpiece structure based on the output of the reaction force measuringdevice and the numerical model, and includes an adder which adds thecalculated result and the output of the shaking table motion measuringdevice, and outputs the added result to the controller.

[0009] It is also preferable that the digital computer stores theshaking wave form of the shaking table, and the digital computer outputsa control signal to the controller based on the output of the reactionforce measuring device, and the digital computer includes time controlmeans which controls a shaking timing of the shaking table.

[0010] It is further preferable that the simulated structure is capableof shaking having a plurality of degrees of freedom.

[0011] It is also preferable that the digital computer includes memorymeans to which the numerical model is inputted, structure motioncalculating means which calculates the motion of the structure after apredetermined period from the time when the reaction force is measuredbased on the outputs of the reaction force measuring device and theshaking table motion measuring device with reference to the numericalmodel stored in the memory means, shaking signal calculating means whichcalculates a shaking signal to be given to the actuator after apredetermined period based on the calculated motion of the structure,and time control means which controls the predetermined time.

[0012] Furthermore, the digital computer may include means for storingthe shaking wave form of the shaking table, while the time control meanscontrols the shaking timing of the shaking table based on this storedshaking wave form.

[0013] The third aspect of the present invention to achieve the aboveobjects is that in a testing method for a structure which tests astructure made of a partial structure and a numerical model virtuallyconnected to this partial structure, the partial structure mounted on ashaking table is shaken by the shaking table and an actuator which isfixedly mounted on a foundation which is the same foundation on whichthe shaking table is mounted, a reaction force generated by the partialstructure and a displacement of the shaking table at this time aremeasured, a motion of a joint between the numerical model and partialstructure after a predetermined period from the time when the reactionforce is measured is obtained based on the measured values of thereaction force and the displacement of the shaking table, and a shakingsignal is inputted to the actuator for realizing the obtained motion atthe joint after a lapse of the predetermined time, and the actuatorshakes the partial structure based on this signal.

[0014] The fourth aspect of the present invention to achieve the aboveobject is that in a testing method for a structure made of a test piecestructure mounted on a shaking table and a numerical model virtuallyconnected to the test piece structure and stored in a digital computer,a step in which the test piece structure is shaken by the shaking tableand an actuator fixedly mounted on a foundation on which the shakingtable is mounted, and a reaction force generated by the test piecestructure is measured, a step in which a displacement of the shakingtable is measured, a step in which the measured value of the reactionforce is inputted to the digital computer, a step in which measureddisplacement of the shaking table is inputted to the digital computer, astep in which a relative motion of the structure to the shaking tableafter a predetermined period from the time when the reaction force ismeasured is calculated from the measured value of the reaction forcewith reference to the numerical model, a step in which a relative motionof the structure to the foundation for the shaking table after apredetermined period from the time when the reaction force is measuredis calculated by adding the calculated result of the relative motion ofthe structure and the measured value of the displacement of the shakingtable, a step in which a shaking signal which makes the motion obtainedby the calculation at a portion of the test piece structure to be shakenby the actuator is calculated, a step in which the shaking signal isoutputted after a predetermined period from the time when the reactionforce is measured, and a step in which the actuator is driven based onthe shaking signal are carried out in sequence.

[0015] The fifth aspect of the present invention to achieve the aboveobjects is that in a testing method for a structure made of a test piecestructure mounted on a shaking table and a numerical model virtuallyconnected to the test piece structure and stored in a digital computer,the test piece structure is shaken by using the shaking table and anactuator fixedly mounted on a foundation on which the shaking table ismounted, a reaction force generated by the test piece structure ismeasured and inputted to the digital computer while a relative motionbetween the structure and the shaking table after a predetermined periodfrom the time when the reaction force is measured is calculated usingthe measured value of reaction force with reference to the numericalmodel, a relative motion of the structure to the foundation for theshaking table after a predetermined period from the time when thereaction force is measured is calculated by adding the calculated resultof the relative motion of the structure and a preliminarily obtaineddisplacement of the shaking table, a shaking force given to the testpiece for making the calculated motion after the predetermined period isobtained, and this shaking force is generated by the actuator.

[0016] The preliminarily obtained displacement of the shaking table ispreferably measured at the time of measuring the reaction force orprestored in the digital computer. It is also preferable that thepreliminarily obtained displacement of the shaking table is the valuemeasured at the time of measuring the reaction force, and aftercalculating the relative motion between the structure and the shakingtable which is carried out after a predetermined period from the timewhen the reaction force is measured, when the motion of the structurerelative to the foundation for the shaking table after a predeterminedperiod is to be obtained, a prestored shaking wave form of the shakingtable is used, and the time lag is calculated from the differencebetween the measured value of the motion of the shaking table and theprestored wave form and the predetermined period is adjusted based onthe time lag to correct the predetermined period.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]Fig. 1 is a schematic view of one embodiment of the shaking testsystem of the present invention.

[0018]FIG. 2 to Fig. 4 are schematic views of modifications thereof.

[0019]Fig. 5 is a flow chart of one embodiment of the shaking testingmethod of the present invention.

[0020]Fig. 6 to FIG. 8 are flow charts of the modifications thereof.

[0021]FIG. 9 is a schematic view of one embodiment of the shakingtesting system of the present invention showing the surroundings of thetest piece structure in detail.

DETAILED DESCRIPTION OF THE INVENTION

[0022] An embodiment of the present invention is hereinafter explainedin conjunction with attached drawings.

[0023]FIG. 1 is a block diagram relating to one embodiment of a shakingtesting system for a structure according to the present invention. Forinstance, to examine the behavior of a bridge girder at the time of anoccurrence of an earthquake, it is impossible to examine the wholebridge girder. Accordingly, a method which cuts out a part of the bridgegirder as a test piece and analyzes the remaining portion of the bridgegirder numerically taking into account that the behavior of the motionof the remaining portion has a strong linearity is used. In such a case,a test piece structure 3 has one end thereof fixedly mounted on ashaking table 5 and the other end thereof connected to a frame 8provided to a front end portion of an actuator 1. The remaining portionsof the test piece structure 3 are not connected to any other members.Here, the actuator 1 is mounted on a rigid wall 7 which is fixedlymounted on a foundation 6 on which the shaking table 5 is also mounted.The actuator 1, the frame 8 and a reaction force measuring device 2constitute a simulated structure. The reaction force measuring device 2measures the reaction force applied to the test piece structure 3 byshaking. So long as the reaction force can be measured, the location ofthe reaction force measuring device 2 is not limited to a position shownin FIG. 1.

[0024] The shaking table 5 is shaken in upper and lower directions bymeans of actuators 31, while the shaking table 5 is shaken in horizontaldirection consisting of an X direction and a Y direction by means ofactuators not shown in drawings. When the shaking table 5 is shaken bythese actuators, the reaction force loaded to the reaction forcemeasuring device 2 from the test piece structure 3 is transmitted tosignal input means 13 by way of signal transmission means 16 andeventually is inputted to a digital computer 10. When the shaking table5 is shaken, a motion value of the shaking table 5 measured by a shakingtable motion measuring device 4 is transmitted to signal input means 12by way of signal transmitting means 15 and this value is also inputtedto the digital computer 10. A shaking signal is transmitted from asignal output means 11 which includes the digital computer 10 to anactuator controller 9 by way of signal transmission means 14. Thesimulated structure is driven by this shaking signal. In case theshaking of the shaking table 5 in upper and lower directions is notnecessary, the actuators 31, may be replaced by a support device whichcan support the shaking table 5 in upper and lower directions.

[0025] In the above-mentioned constitutional components, to be morespecific, the transmission signals are voltage signals, the signaltransmission means are cables, the signal input device is an A/Dconverter and the signal output device is a D/A converter. However, theabove-mentioned constitutional elements are not limited to these partsbut may be made of other ways.

[0026] In the digital computer 10, the measured value of the motion ofthe shaking table 5 and the measured value of the reaction force whichare inputted from the signal input means 12 and the signal input means13 respectively are outputted to structure motion calculating means 17.A numerical model is inputted and stored in the structure motioncalculating means 17. This numerical model is a virtual structureconnected to the test piece structure 3 and is made of a matrix ofcoefficients and various constants of equations of motions and can bepreliminarily obtained by an auxiliary device of the digital computernot shown in drawings.

[0027] The structure motion calculating means 17 numerically integratesthe equations of motion with the measured value of the reaction force asan external force using the numerical model. Thus, the condition of therelative motion between the numerical model and the shaking table isobtained by calculation. By combining the calculated result and themeasured value of motion of the shaking table 5, the condition of themotion of the numerical model relative to the foundation 6 after a givenperiod or a predetermined period from the time when the reaction forceis measured is obtained. Although the central difference method can bepreferably used as the numerical integration, the numerical integrationis not limited to such a method.

[0028] This calculated result is inputted to shaking signal calculatingmeans 18 and a shaking signal to the actuator 1 is generated such thatafter a given period or a predetermined period, the motion of a jointbetween the test piece structure 3 and the simulated structure 30coincides with the result calculated by the structure motion calculatingmeans 17. This shaking signal is outputted from signal output means 11.The digital computer 10 is controlled by time control means 19 such thatthe prediction of motion calculation of the test piece structure after alapse of a given time or a predetermined time is actually obtained afterthe given time or the predetermined time.

[0029] According to the present embodiment, even when the actuator isnot mounted on the shaking table, an experiment can be carried out byemploying the simulation and the numerical calculation and hence, theexperiment which makes full use of the size of the shaking table becomespossible.

[0030] A modification of the above-mentioned invention is explainedusing a block diagram shown in FIG. 2.

[0031] In the embodiment shown in FIG. 1, the signal measured by themeasuring device 4 which measures the motion of the shaking table 5 isinputted to the signal input means 12. However, in this modification,the signal is directly inputted to a signal adder 21 which is disposedbetween the signal output means 11 and the controller 9 for the actuator1. This modification is different from the embodiment shown in FIG. 1 onthis point. Accordingly, the same parts which appear in the embodimentshown in FIG. 1 are given the same symbols. In the signal adder 21,based on the measured value of the motion of the shaking table 5measured by the measuring device 4, the measured signal is converted toa shaking signal which makes the motion of the measured values. Parallelwith the above operation, a shaking signal transmitted from the digitalcomputer 10 by way of the signal transmission means 14 is added to theprevious shaking signal and its output signal is inputted to thecontroller 9 for the actuator 1 by way of the signal transmission means22.

[0032] According to this modification, even when the actuator is notmounted on the shaking table, the testing of a structure becomespossible by the combined use of the conventional simulation and thenumerical calculation.

[0033] Another modification of the present invention is explained usinga block diagram shown in FIG. 3. The difference between thismodification and the above-mentioned embodiment is that thismodification does not use an output of motion of the shaking tablemeasured by the shaking table motion measuring device 4 for the controlof the actuator 1. Accordingly, the motion of the shaking table must besimulated by any suitable forms. In this modification, the wave form ofthe motion of the shaking table is preliminarily stored by an auxiliarydevice of the digital computer such as memory means.

[0034] By combining the condition of the relative motion between thenumerical model calculated by the digital computer 10 and the shakingtable and a preliminarily inputted wave form of the motion of theshaking table, the condition of the motion of the numerical modelrelative to the foundation 6 after a predetermined period from the timewhen the reaction force is measured is obtained. Although, in FIG. 3, acase in which the time control means 19 controls the shaking table 5 isshown, the control range of the time control means 19 may be restrictedwithin the digital computer 10 and the time control function that theshaking table 5 has is used as time control means of an upper order.

[0035] According to this modification, a testing of a structure can becarried out by only altering the programming of structure motioncalculation means and adding time signal transmission means between theshaking table and the time control means in a conventional earthquakeresistance testing method for the structure which uses the conventionalsimulation and the numerical calculation in parallel. Accordingly, thecost for the test can be reduced and the test can be simplified.

[0036] Still further modification of the present invention is explainedusing a block diagram shown in Fig. 4. This modification ischaracterized by providing the time control relationship between theshaking table and the time control means 19 shown in FIG. 1.

[0037] In the memory device of the digital computer 10, as in the caseof the modification shown in FIG. 3, the numerical model and the waveform of the motion of the shaking table are stored. The condition of themotion of the shaking table relative to the foundation 6 after apredetermined period from the time when the reaction force is measuredis calculated based on the condition of the relative motion of thenumerical model to the shaking table which is calculated by thestructure motion calculating means 17 and the time lag between thepreliminarily inputted wave form of the motion of shaking table and thewave form of the measured value of the motion of the shaking table.Here, the wave form of the motion of the shaking table at the time whichprecedes by the time lag is obtained from the preliminarily stored waveform of the motion of the shaking table and the measured value iscorrected by this value. The relationship between the shaking table 5and the digital computer 10 is similar to that of the case shown in FIG.3 and hence, the detailed explanation thereof is omitted. According tothis modification, the calculation of the motion of the structure higherthan that of the embodiment shown in FIG. 1 can be achieved.

[0038] One embodiment and its respective modifications of the testingmethod for a structure which are carried out using the systems shown inthe above-mentioned embodiment and its respective modifications areexplained in detail in conjunction with Fig. 5 and ensuing drawings.Fig. 5 is shows an embodiment which uses the testing system for thestructure shown in FIG. 1. In this embodiment, an earthquake resistancetest of a structure is carried out in accordance with following steps.

[0039] (1) First of all, the actuators 31 or the like for the shakingtable 5 shake the test piece structure 3. The reaction force generatedby the test piece structure 3 is measured by the reaction forcemeasuring device 2 (step 110).

[0040] (2) Simultaneously, the displacement of the shaking table 5 ismeasured by the shaking table motion measuring device 4 (step 120).

[0041] (3) Subsequently, the reaction force value measured by thereaction force measuring device 2 in the step 110 is inputted to thedigital computer 10 (step 130).

[0042] (4) The displacement of the shaking table measured by the shakingtable motion measuring device 4 in the step 120 is inputted to thedigital computer 10 (step 140).

[0043] (5) Based on the numerical model of the structure preliminarilyinputted to the digital computer 10, the structure motion calculatingmeans 17 calculates the motion of the structure after a predeterminedperiod from the time when the reaction force is measured using thereaction force value measured in the step 110. Here, the structure iscomprised of the numerical model and the test piece structure 3, whilethe motion means the relative motion between the structure and theshaking table 5 (step 150).

[0044] (6) The structure motion calculating means 17 adds the measuredvalue of the displacement of the shaking table obtained in the step 140to the motion of the structure obtained in the step 150 and calculatesthe motion of the structure after a predetermined period from the timewhen the reaction force is measured. Here, the motion means the motionof the shaking table 5 relative to the foundation, namely, the absolutedisplacement (step 160).

[0045] (7) Based on the calculated result of the motion of the structureobtained in the step 160, the shaking signal calculating means 18calculates a shaking signal for the actuator 7 which is necessary forobtaining the condition of the motion to be made by the simulatedstructure 30 (step 170).

[0046] The signal output device 11 outputs the shaking signal obtainedin the step 170 after a predetermined period (step 180).

[0047] (8) Based on the shaking signal outputted from the signal outputdevice 11, the controller 9 drives the actuator 1 (step 190).

[0048] (9) Here, the completion or the end of the shaking test for astructure is determined whether a preliminarily set time has lapsed ornot or whether a stop signal is given to the actuator controller or not.This determination means may be incorporated in the digital computer 10or the actuator controller 9 or may be provided as a separate device.

[0049] According to this embodiment, due to the combined use of theshaking test of the partial structure and the numerical calculationusing the numerical model, the earthquake resistance test for astructure becomes possible without mounting the actuator on the shakingtable and hence, the entire space of the shaking table can beeffectively used. Accordingly, the ratio between the mounting area forthe partial structure and the area of the shaking table can be made asclose as possible to 1.

[0050] Subsequently, the modification of the testing method for astructure using the testing system for a structure shown in FIG. 2 isexplained in view of FIG. 6. This testing method differs from theabove-mentioned embodiment in that the displacement of the shaking table5 and the displacement of the actuator 7 are separated. To be morespecific, In the testing method shown in FIG. 5, the steps 150-170 arereplaced with the following steps 210-230 and steps 270, 280 and steps250, 260 are added.

[0051] (5a) Based on the numerical model of the structure preliminarilyinputted to the digital computer 10, the motion of the structure after apredetermined period from the time when the reaction force is measuredis calculated using the reaction force value measured in the step 110.Here, the motion of the structure means the relative motion between thestructure and the shaking table 5 (step 210).

[0052] (6a1) From the calculated result of the motion of the structureobtained in the step 210, the shaking signal calculating means 18calculates a shaking signal for the actuator 1 necessary for obtainingthe condition of the motion to be made on the simulated structure 30after a predetermined period (step 220).

[0053] (6a2) The signal output device 11 outputs the shaking signalobtained in the step 220 after the predetermined period (step 230).

[0054] Furthermore, parallel to the above-mentioned steps for shakingthe test piece structure, steps for controlling the displacement of theshaking table 5 are carried out.

[0055] (4a1) The measured value of the displacement of the shaking tableobtained in the step 120 is inputted to the adder 21 by way of thesignal transmission means 15 (step 250).

[0056] (4a2) In the adder 21, based on the displacement of the shakingtable measured by the shaking table motion measuring device 4, a secondshaking signal for shaking the shaking table after the predeterminedperiod is obtained and the adder 21 outputs this second shaking signal(step 260).

[0057] (6a3) A first shaking signal of the structure obtained by thedigital computer 10 is inputted to the adder 21 (step 270).

[0058] (7a) The first shaking signal of the structure obtained by thedigital computer 10 and the second shaking signal are combined in theadder 21 and are converted to a third shaking signal (step 280).

[0059] According to this modification, while using the conventionalshaking table without any change, due to the combination of the shakingtest of the partial structure and the numerical calculation of thenumerical model, the earthquake resistance test for a structure can becarried out with a high precision.

[0060] The modification of the testing method for a structure using thetesting system for a structure shown in FIG. 3 is explained in view ofFIG. 7. This testing method differs from the above-mentionedmodification shown in FIG. 5 in that the method does not use the outputof the shaking motion measuring device. Namely, the motion of theshaking table 5 is stored in memory means and based on this storedmotion, the time control means 19 controls the motion of the shakingtable 5. Accordingly, in the steps 110-160 of the first shaking testembodiment, the steps 120 and 140 are omitted and the steps 150 and 160are changed to the following steps 310, 320.

[0061] (5b) With respect to the numerical model of the structure whichis prestored in the digital computer 10, the structure motioncalculating means 17 calculates the relative motion of the structure tothe shaking table after a lapse of a predetermined period from the timewhen the reaction force is measured (step 310).

[0062] (6b) By adding a preliminarily stored or inputted shaking waveform of the shaking table to the calculated result of the motion of thestructure obtained in the step 310 using the structure motioncalculating means 17, the motion of the structure relative to thefoundation for the shaking table after the predetermined period from thetime when the reaction force is measured is calculated (step 320).

[0063] Thereafter, the step 170 and ensuing steps are carried out.According to this modification, in addition to the advantage of theembodiment of the first testing method, by merely adding the signaltransmission means for performing the time control between the shakingtable and the digital computer to the conventional shaking table andaltering the programming related to such an addition, an earthquakeresistance test of a large-scaled structure can be carried out using thesimple numerical model and the partial structure.

[0064] The modification of the testing method for a structure using thetesting system for a structure shown in FIG. 4 is explained in view ofFIG. 8. This testing method is characterized by adding a time control ofthe shaking table to the testing method shown in FIG. 5. Namely, inplace of the step 160, steps 410-430 are carried out.

[0065] (6c1) Based on the shaking wave form of the shaking table whichis preliminarily inputted to the digital computer 10, the displacementof the shaking table after a predetermined period from the time when thereaction force is measured is obtained. By combining this value and thecalculated result of the relative motion of the structure after thepredetermined period, the structure motion calculating means calculatesthe motion of the structure relative to the foundation for the shakingtable after the predetermined period (step 410).

[0066] (6c2) By comparing the preliminarily inputted shaking wave formof the shaking table with the measured value measured by the shakingtable displacement measuring means 4, the structure motion calculatingmeans calculates the time lag between the wave form obtained by plottingthe measured values measured by the shaking table displacement measuringmeans 4 at a predetermined time interval and the shaking wave form ofthe shaking table (step 420).

[0067] (6c3) Based on the time lag obtained in the step 420, the timecontrol means 19 adjusts the predetermined time interval from the timewhen the reaction force is measured necessary for calculating theabsolute displacement of the structure, and renews the predeterminedtime interval (step 430).

[0068] According to this testing method, an earthquake resistance testcan be carried out with a higher precision.

[0069] Although the actuator 1 is described as an actuator havingone-dimensional excitation capability in any one of the above-mentionedtesting methods, it is needless to say that the actuator 1 may be anactuator having two or more-dimensional excitation capability.Furthermore, the shaking direction of the shaking table may be eitherone horizontal direction or two horizontal directions, or the shakingmay be generated by applying impacts on the shaking table. Stillfurthermore, the predetermined period can be a fixed time or a valuecalculated by the computer.

[0070] Furthermore, in FIG. 9, a case where the structure is shaken by aplurality of actuators is shown. The test piece structure 3 is mountedon the shaking table 5 and is shaken in vertical directions by twoactuators 1, and in a horizontal direction by one actuator 1. Althoughnot shown in drawings, the shaking table 5 is provided with shakingmeans in respective directions for enabling the shaking of the shakingtable 5 in vertical directions as well as in horizontal directions. Asmentioned previously, the reaction forces applied to the actuators 1,from the test piece structure 3 are measured by the reaction forcemeasuring device 2, while the motion of the shaking table 5 is measuredby the shaking table motion measuring device 4. The construction ofother components or parts is the same as that of the above mentionedembodiments and modifications and hence, the detailed explanation isomitted. According to this embodiment, since the structure is shakenwith a plurality of degrees of freedom using a plurality of actuatorsand hence, more actual or realistic simulation test can be carried out.Although the part which constitutes the numerical model is omitted inFIG. 9, it is needless to say that a so-called hybrid shaking test iscarried out using the numerical model.

[0071] Although respective embodiments and respective modifications ofthe present invention have been explained heretofore, the presentinvention substantially can take various forms within its scope withoutdeparting from the gist of the invention. Accordingly, the previouslymentioned embodiments and modifications are simply illustrations of thepresent invention in any aspects and they should not be construed tolimit the present invention. Furthermore, modifications which belong toa scope of equivalence of the claims fall within the scope of thepresent invention.

[0072] According to the present invention, when the partial structuremounted on the shaking table is shaken by the shaking table and theactuators which are fixedly mounted on the foundation on which theshaking table is also mounted, the shaking response of the structuremade of the partial structure and the numerical model virtuallyconnected to the partial structure is calculated by the digital computerand the calculated result is made by the shaking table and the actuatorand hence, the test of the large-sized test piece structure which makesfull use of the size of the shaking table can be carried out.

What is claimed is:
 1. A testing system for a structure which tests astructure made of a partial structure and a numerical model virtuallyconnected to said partial structure, comprising: a shaking table onwhich said partial structure is mounted, a simulated structure whichincludes an actuator for shaking said partial structure and reactionforce measuring means for measuring a reaction force which saidsimulated structure receives from said partial structure when saidpartial structure is shaken, and a digital computer which calculates themotion of said numerical model based on the measured value of saidreaction force measuring means and generates a shaking signal for saidactuator based on the calculated result, and said shaking table and saidsimulated structure are mounted on a common foundation.
 2. A testingsystem for a structure comprising a shaking table which is mounted on afoundation by way of a first actuator, a simulated structure having atleast one second actuator which is fixedly mounted on a foundation whichis common to a foundation on which said shaking table is mounted, areaction force measuring device which measures a reaction forcegenerated by a test piece structure connected to said simulatedstructure, a digital computer which stores a numerical model virtuallyconnected to said test piece structure, a controller which controls saidsimulated structure, and a shaking table motion measuring device whichmeasures the motion of said shaking table.
 3. A testing system for astructure according to claim 2, wherein said digital computer outputs acontrol signal based on the output of said shaking table motionmeasuring device and said reaction force measuring device to saidcontroller.
 4. A testing system for a structure according to claim 2,wherein said digital computer calculates the motion of said test piecestructure based on the output of said reaction force measuring deviceand said numerical model, and includes an adder which adds thecalculated result and the output of said shaking table motion measuringdevice, and outputs the added result to said controller.
 5. A testingsystem for a structure according to claim 2, wherein said digitalcomputer includes time control means which controls the shaking timingof said shaking table and stores the shaking wave form of said shakingtable, and said digital computer outputs a control signal to saidcontroller based on the output of said reaction force measuring device.6. A testing system for a structure according to claim 1, wherein saidsimulated structure is capable of shaking having a plurality of degreesof freedom.
 7. A testing system for a structure according to claim 2,wherein said simulated structure is capable of shaking having aplurality of degrees of freedom.
 8. A testing system for a structureaccording to claim 1, wherein said digital computer includes memorymeans to which said numerical model is inputted, structure motioncalculating means which calculates the motion of said structure after apredetermined period from the time when the reaction force is measuredbased on the outputs of said reaction force measuring device and saidshaking table motion measuring device with reference to said numericalmodel stored in said memory means, shaking signal calculating meanswhich calculates a shaking signal to be given to said actuator after thepredetermined period based on the calculated motion of said structure,and time control means which controls the predetermined period.
 9. Atesting system for a structure according to claim 2, wherein saiddigital computer includes memory means to which said numerical model isinputted, structure motion calculating means which calculates the motionof said structure after a predetermined period from the time when thereaction force is measured based on the outputs of said reaction forcemeasuring device and said shaking table motion measuring device withreference to said numerical model stored in said memory means, shakingsignal calculating means which calculates a shaking signal to be givento said actuator after a predetermined period based on the calculatedmotion of said structure, and time control means which controls thepredetermined period.
 10. A testing system for a structure according toclaim 8, wherein said digital computer includes means for storing theshaking wave form of said shaking table, and said time control meanscontrols the shaking timing of said shaking table based on said storedshaking wave form.
 11. A testing system for a structure according toclaim 9, wherein said digital computer includes means for storing theshaking wave form of said shaking table, and said time control meanscontrols the shaking timing of said shaking table based on said storedshaking wave form.
 12. A testing method for a structure which tests astructure made of a partial structure and a numerical model virtuallyconnected to said partial structure, the improvement is characterized inthat said partial structure mounted on a shaking table is shaken by anactuator which is fixedly mounted on a foundation which is the samefoundation on which said shaking table is mounted and said shakingtable, a reaction force generated by said partial structure and adisplacement of said shaking table at this time are measured, a motionof a joint between said numerical model and said partial structure aftera predetermined period from the time when a reaction force is measuredhour is obtained based on the measured values of said reaction force andthe displacement of said shaking table, and a shaking signal is inputtedto said actuator for making the obtained motion at said joint after thepredetermined period, and said actuator shakes said partial structurebased on said signal.
 13. A testing method for a structure made of atest piece structure mounted on a shaking table and a numerical modelvirtually connected to said test piece structure and stored in a digitalcomputer, the improvement is characterized in that said test piecestructure is shaken by said shaking table and an actuator fixedlymounted on a foundation on which said shaking table is mounted, and astep in which a reaction force generated by said test piece structure ismeasured, a step in which a displacement of said shaking table ismeasured, a step in which the measured value of said reaction force isinputted to said digital computer, a step in which the measureddisplacement of said shaking table is inputted to said digital computer,a step in which a relative motion of said structure to said shakingtable after a predetermined period from the time when the reaction forceis measured from the measured value of the reaction force is calculatedwith reference to said numerical model, a step in which a relativemotion of said structure to said foundation of the shaking table afterthe predetermined period from the time when the reaction force ismeasured by adding the calculated result of the relative motion of saidstructure and the measured value of the displacement of said shakingtable is calculated, a step in which a shaking signal which makes themotion obtained by the calculation at a portion of said test piecestructure to be shaken by said actuator is calculated, a step in whichthe shaking signal is outputted after the predetermined period from thetime when the reaction force is measured, and a step in which saidactuator is driven based on the shaking signal, are carried out insequence.
 14. A testing method for a structure made of a test piecestructure mounted on a shaking table and a numerical model virtuallyconnected to said test piece structure and stored in a digital computer,the improvement is characterized in that said test piece structure isshaken by using said shaking table and an actuator fixedly mounted on afoundation on which said shaking table is mounted, a reaction forcegenerated by said test piece structure is measured and inputted to saiddigital computer while a relative motion between said structure and saidshaking table after a predetermined period from the time when thereaction force is measured is calculated using the measured value of thereaction force with reference to the numerical model, a relative motionof said structure to said foundation for said shaking table after thepredetermined period from the time when the reaction force is measuredis calculated by adding the calculated result of the relative motion ofsaid structure and a preliminarily obtained displacement of said shakingtable, a shaking force given to said test piece for making thecalculated motion after the predetermined period is obtained, and saidshaking force is generated by said actuator.
 15. A testing method for astructure according to claim 14, wherein said preliminarily obtaineddisplacement of said shaking table is measured at the time of measuringthe reaction force.
 16. A testing method for a structure according toclaim 14, wherein said preliminarily obtained displacement of saidshaking table is prestored in the digital computer.
 17. A testing methodfor a structure according to claim 14, wherein the preliminarilyobtained displacement of said shaking table is the value measured at thetime of measuring the reaction force, and after calculating the relativemotion between said structure and said shaking table which is carriedout after a predetermined period from the time when the reaction forceis measured, when the motion of said structure relative to saidfoundation for said shaking table after the predetermined period is tobe obtained, a prestored shaking wave form of said shaking table isused, and the time lag is calculated from the difference between themeasured value of the motion of said shaking table and the prestoredwave form and the predetermined time is adjusted based on said time lagto correct the predetermined time.